This summary information on persistence, bioaccumulation and toxicity comes from Fass. The risk comes from the report from Goodpoint.
Persistence. Zolpidem is potentially persistent.
Bioaccumulation. Zolpidem has low potential for bioaccumulation.
Toxicity. Zolpidem has moderate chronic toxicity.
Risk. Zolpidem is poorly investigated, but existing data indicate low environmental risk.
Zolpidem is a benzodiazepine-like hypnotic. The benzodiazepine oxazepam has been shown to alter the behavior of fish which can give potential effects on the ecological balance. Further research is ongoing.
Fass environmental information for Stilnoct (zolpidem) from Sanofi AB (downloaded 2021-10-27).
Persistence: "Ready biodegradability: Test showed 30 % degradation in 28 days. (OECD 301). Zolpidem fails to pass the criteria for ready and inherent biodegradability. The phrase: "Zolpidem is potentially persistent” is thus chosen."
Bioaccumulation: Log P = 1.2 at neutral pH (estimated)."
Toxicity: There are data for 3 trophic levels, most sensitive fish (Danio rerio) 33 d (mortality) = 253 microg/L.
PEC/PNEC is based on sales data in Sweden in year 2019. PEC/PNEC = 0.011 which gives the risk insignificant.
Zolpidem is poorly investigated, but existing data indicate low environmental risk.
Zolpidem has been detected in treated wastewater in Region Stockholm.
Author: Health and Medical Care Administration, Region Stockholm